The acceleratory degradation of solids represents an area of research where extreme care must be exercised to obtain reproducible data. Different preparations of the same substance often show great variation in degradation patterns. Many kinetic equations have been developed to describe the kinetics of acceleratory degradations. Most of them are empirical and apply only to certain phases of a degradation. The non-steady-state kinetics which were developed to describe the zip degradation of poly(vinyl chloride) will be shown to describe effectively the unusual degradation behavior of inorganic solids that follow an acceleratory pattern.